Field of the Invention
The present invention relates to an apparatus for forming a dye image on an image receiving material by transferring a movable dye image formed on a heat developed photosensitive material onto the image receiving material in the presence of an image forming solvent.
Description of the Prior Art
As shown in Japanese Patent Laid-Open No. 75247/1984, an image forming apparatus for obtaining a color image by a heat developed photosensitive material is known in which, after an image is exposed on a heat developable photosensitive material, the photosensitive material is moved to a heat development section, and a movable dye is transferred onto an image receiving material by causing the image receiving material to adhere to the heat-developed photosensitive material, thereby obtaining a dye image. Furthermore, Japanese Utility Model Application No. 116734/1986 discloses an apparatus in which an exposed heat developable photosensitive material is adhered to an image receiving material and is subjected to heating, so that heat development and transfer of the dye are effected simultaneously.
An image forming solvent such as water is applied to the photosensitive material and/or the image receiving material prior to the transfer process or the heat development process so as to accelerate the transfer of the dye or the development.
This image forming solvent is supplied to the photosensitive material and/or the image receiving material by any of various methods such as one in which roller application or wire bar application is used, as disclosed in Japanese Patent Laid-Open No. 181353/1984, one in which a water absorbent member is used, as disclosed in Japanese Patent Laid-Open No. 181354/1984, one based on bead application as disclosed in Japanese Patent Laid-Open No. 181346/1984, one based on bead application using a water repellant roller, as disclosed in Japanese Patent Laid-Open No. 181348/1984, or a method involving dip application.
In order to effectively use the image forming solvent, the image forming solvent is circulated between a solvent supplying section, such as a section which effects the aforementioned application, and a solvent storage section.
However, if the image forming solvent is reused by circulating it, as described above, gelatine and other components are exfoliated or eluted from the photosensitive material and/or the image receiving material into the solvent, depending on the frequency of use. Consequently, fungi and bacteria are likely to be produced, with the result that the solvent becomes contaminated. If such contamination occurs, a problem arises in that the device which supplies the solvent becomes contaminated and impedes the supply of the solvent, or the contaminants are interposed between the photosensitive material and the image receiving material, thereby hampering the development or transfer.